In this proposed research project, we will: (1) develop and implement a new quasi- experimental method that which exploits information on the random nature of certain biological processes of human fetal development, namely the occurrence of chromosomally aberrant miscarriages, in conjunction with survey data, to put statistically robust and tight lower and upper bounds on the effect of teenage and/or illegitimate childbearing on a range of socioeconomic outcomes of the mother as an adult; (2) test economic and sociological theories of why some women have children as teenagers while others do not by validating whether estimators that incorporate these theories yield estimates of teenage childbearing that lie within our bounds; and (3) use alternative types of information and/or assumptions in conjunction with our non-parametric bounds to explore ways to tighten our proposed non-parametric bounds of the causal effects of early and out-of-wedlock childbearing so that they are more precise and to examine less highly parameterized versions of the types of behavioral assumptions, such comparative advantage and/or common factor structures, used in previous studies. Using data from the National Longitudinal Study of Youth (NLSY) and supplementary data from a variety of sources to generate estimates of incidence rates of chromosomally aberrant miscarriages and other reproductive events, we will develop this new methodology to investigate the effects of teenage and out- of-wedlock childbearing on: high school completion rates, post-high school educational attainment, the labor force participation rates and wages achieved, the propensity to marry and remain married, the propensity to receive welfare, and the propensity to live in poverty, where these outcomes will be measured when the woman is in her late 20's.